The present invention relates to a portable terminal. In particular, the invention relates to a portable terminal for encrypting information and to a method of encrypting information in a portable terminal, such as a personal digital assistant (PDA).
PDAs are used for storing personal information and for transferring stored personal information between computer systems. It is also possible to use a PDA to prepare and store highly confidential personal information such as transaction information for execution at a self-service terminal (SST) such as an automated teller machine (ATM).
To provide some security for the transaction information it would be desirable to encrypt the transaction information that is stored on and transmitted from the PDA. However, a conventional PDA is not an inherently secure device; it has minimal tamper resistance, which means that there is no secure area for storing a secret cryptographic key. The lack of secure storage means that industry-standard cryptographic techniques cannot be used with a conventional PDA.